The Study Of Directed Flow In U+U Collisions At 600AMeV

The major goal of high energy heavy-ion collisions is to extract informationabout the properties of nuclear matter at high density, higt temperature and high pres-sure, then to obtain the nuclear equation of state. However , it is impossible to measurethe properties of the nuclear matter directly under such coditions in experiment. Sowe need to find a observable of final state which can describe the nuclear matter atextreme condition, get the property of nuclear matter. The calculation of nuclear hy-drodynamical point out that the collective ?ow of final state is a observable quantityto study the nuclear matter at extreme condition and is a important tool to obtain thenuclear equation of state.In this paper, We used the transport model RQMD to study the directed ?ow inU+U collisions at 600AMeV . The paper study the multiplicity dependence of im-pact parameter, provide the relation of multiplicity and centrality. We used differentmethod to analysis directed ?ow in U+U collisions at 600AMeV . We study averagein?plane transverse momentum as a function of rapidity for different impact param-eter, show the directed ?ow dependence of impact parameter and point the relationof ?ow and stopping. we used two method to analysis the anisotropy of azimuthaldistribution, Fourier expansion of azimuthal distribution and particle-pair correlation.We find that particle-pair correlation have large statistical error at large rapidity anddon't analysis directed ?ow at intermediate rapidity.The paper also investigate the time dependence of the directed ?ow. At the earlytime, the directed ?ow have a different distributions, at later time, this distributionvanished. This is because nucleon'time less than nuclear passing time at early time.At early time the directed ?ow is strongly in?uenced by the spectators. at later times,a prominent in-plane emission is evident, the modification vanished.